Drive for grinding-mills



R. R. HOWELL.

DRIVE FOR GRINDING MILLS.

APPLICATION FILED MAR. 28. 1919.

1,328,834. Patented Jan. 27, 1920.

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ROBERT R. L-IoWELL, or MINNEAPOLIS, MINNESOTA.

-- DRIVE non GRINDING-MILLS.

To all whom it may concern: a

Be it known that I, ROBERT R. HOWELL, a citizen of the United States, resident of Minneapolis,-county of Hennepin, State of Minnesota, have invented certain new and useful Improvements in Drives for Grinding-Mills, of which the followingis a spec1- fication. Q-

My invention relates to;' the. driving of grinding rolls at difierent speeds and with a single belt, of a mill for grinding or reducing grain of various kinds or other s mllar material.

In installing mills of that character w1th ordinary drives it is often found that where a single belt is utilized to drive the cooperating grinding rolls that the arc of contact with the belt on the pulleys will vary with the location of the source of power and often the contacting arc is diminished so much by a high or low location of the driving shaft or source of power that special idler pulleys must be installed to provide for the necessary wrap of belt on the pulleys.

The object of the invention is to provide means whereb the cooperating grinding rolls maybe drlven at different rates of speed in opposite directions with a single belt having a large effective arc of contact with the pulleys of the driven rolls and in which the location of driving pulley, constituting the source of power, may vary greatly in altitude without changing the arc of contact of the belt with the pulleys.

In the accompanying drawings forming part of this specification,

Figure l is a side View, partially in section, through a grinding mill embodying my invention,

Fig. 2 is a plan view of the same,

Fig. 3 is a diagrammatical view illustrating a modification.

For the sake of clearness I have shown and briefly described features common to grinding mills of this class but the invention specifically consists in the constructions and combinations of the driving mechanism as hereinafter described and particularly pointed out in the claims. I

In the drawing, 2 represents the base of the mill, having a casing 3 supported thereon, provided with a' hopper 4. The grinding rolls are indicated by dotted lines, as they form no part of my present invention. 5 is a shaft of one roll and 6 a pulley se- Specification of Letters Patent.

Patented Jan. 27, 1920.

Application filed March 28. 1919. Serial No. 285,806.

cured thereon. 7 is a shaft of the other roll and 8 a pulley of larger diameter than the pulley 6. The shaft 7 for carrying the grinding roll is journaled in arms 9 pivoted at 10 on the machine casing '011 one side of the shaft and the arms 9 are provided with rods 11 on the other side of the shaft which carry compression springs 12 and have nuts 13 for regulating the tension of said springs. Said rods are eccentrically mounted at 14 on the machine casing and a rod 15 has a crank connection indicated by dotted lines with said eccentric bearing and is provided with an operating lever 16 for movin the said rod 15 lengthwise and rocking said eccentric bearing to swing the said arms 9 and move the grinding roll supported by theshaft 7 toward or from the other roll.

At a point below the outer line of the rolls adjacent the large roll pulley 8 and opposite the small roll pulle 6 I mount an idler pulley 17 on a suitable ournal 18 upon a frame bracket 19. The vertical location of the center of the idler pulley is dependent on the size of the pulley but it is preferably spaced so that a line drawn between the lower peripheries of the pulleys 17 and 6 will be just sufliciently below the periphery of the large roll pulley 8 for clearance of the belt 20. This belt coming froma driving pulley not shown, runs under the idler pulley 17, andaround under the small roll pulley 6, thence under the lar e roll pulley 8 and back over the idler pufiey 17 to the driving pulley or source ofpower. By reference to the dotted lines in Fig. 1 it will be seen that the source of power for pulley 6 may be located at a dlstance below or above the mill without afi'ectin the arc of contact of the belt with the ro pulleys or the efficiency of the drive as the idler pulley 17 compensates for a great variation in d1- rections of the belt, without adversely affecting the driving efliciency of the'belt. It

'is also clear the idler pulley being in front of the pulleys 6 and 8 provides a long are of contact with both pulleys and that the pull of the belt running in the direction of the arrow will rotate the pulleys in opposite,

directions and also exert an upward tightening pressure against the lower periphery of thepulley 8 for preventing slipping. By

reference to Fig. 3 it will also be seen that the idler pulley can be located the same distance above the centerof the roll pulleys with substantiallythe same results and other modifications might be made without departing from the principle of the invention.

I claim as my invention:

1. In a grinding mill the combination with driving pulleys of grinding rolls and a single belt for driving said pulleys, of an idler pulley arranged adjacent'to oneof said pulleys on the side thereof remote from the other driving pulley, the belt running from the source of power under the idler pulley and. around the driving pulley re- :note from the idlerthence back under an arc of the drivingpulley adjacent theidler and over the idler to the source of power, the pull of the belt being away from the mill and in the direction of the source of power. i

2.,The combination with driving pulleys 'frointhe idler pulley and back'to' theidler pulley and thes'ource of power, one of the runs of the belt having a driving contact with the driving puuey-adjacent summer I 'p l a In witness whereohi have hereunto set my hand this 24th da 'tfMerch 1919. g ROBERT R. HOWELL. Witnesses:-

L. B. FELDMAN, WALTER E. 

